How to change b/ground colour w/out touching the image

[seasonalblue]

Hi all photoshop expert..

I need some help.

I took my own passport photo using my digital camera. Now....the background of my picture seems to be greyish in colour although I took it against a white background. I need to change the background colour to more white or off-white without changing the image. Anyone has any idea how to do it?

Really appreciate your fast response.

Thanks.

[Grafixman]

Look at this:

http://pdesigner.net/photoshopcs/1_24_1_0.html